Composite pressure vessel assembly with an integrated nozzle assembly

ABSTRACT

A pressure vessel assembly includes a vessel having a wall defining a chamber and a circumferentially continuous lip projecting into the chamber from the wall. The lip defines a through-bore that is in fluid communication with the chamber. A nozzle assembly of the pressure vessel assembly includes a tube projecting at least in-part into the through-bore, and an o-ring disposed between, and in sealing contact with, the tube and the lip.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with Government support under AgreementDE-AR0000254 for ARPA-E Low Cost Hybrid Materials and Manufacturing forConformable CNG Tank. The Government has certain rights in theinvention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of PCT/US2016/028934 filed Apr. 22,2016, which is incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to a pressure vessel assembly and moreparticularly to a pressure vessel assembly with an integrated nozzleassembly.

Pressure vessels may serve as storage media (e.g., gas) for a widevariety of consumer, commercial, and industrial processes. In order tostore sufficient gas for any operation within a given volume, the gas isstored at high pressure. Traditionally, pressure vessels have a typicalspherical or cylindrical design that evenly distributes stress in thecontainment perimeter. Unfortunately, such tanks do not use allocatedspace efficiently. For example, a spherical vessel fills a cubic spacewith about fifty-two percent efficiency, and a cylindrical vessel fillsa rectangular volume with approximately seventy-eight percentefficiency. More recent improvements in pressure vessels that generallyconform to a rectangular volume may fill the space with about ninetypercent efficiency relative to a true rectangular volume.

The designs of non-spherical/cylindrical pressure vessels to supporthigh internal pressure are complex, including variable-curvatureexternal surfaces and internal structure to transfer mechanical loads.The large size of a high conformable vessels and the complicated shapesmakes manufacturing challenging. The transfer or distribution of stressand related reliability of the pressure vessel itself is furtherchallenged with the integration of various nozzles and ports in thepressure vessels. In addition, manufacturing needs to consistentlyprovide reliable, high-volume, lightweight and low-cost constructions.

SUMMARY

A pressure vessel assembly according to one, non-limiting, embodiment ofthe present disclosure includes a vessel including a wall defining achamber and a circumferentially continuous lip projecting into thechamber from the wall, the lip defining a through-bore in fluidcommunication with the chamber; and a nozzle assembly including a tubeprojecting at least in-part into the through-bore, and an o-ringdisposed between and in sealing contact with the tube and the lip.

Additionally to the foregoing embodiment, the nozzle assembly includes aflange projecting radially outward from the tube and in contact with thewall.

In the alternative or additionally thereto, in the foregoing embodiment,the tube includes a first portion projecting axially inward from theflange and into the through-bore and an opposite second portionprojecting axially outward from the flange.

In the alternative or additionally thereto, in the foregoing embodiment,the first portion includes an outer surface having a contour constructedand arranged to engage the lip.

In the alternative or additionally thereto, in the foregoing embodiment,the contour is circumferentially continuous.

In the alternative or additionally thereto, in the foregoing embodiment,the contour is a barb constructed and arranged to produce a sealingfriction between the lip and the outer surface when the pressure vesselassembly is under a positive pressure.

In the alternative or additionally thereto, in the foregoing embodiment,an internal pressure in the chamber biases the lip radially inwardagainst the barb, and wherein the o-ring is resiliently compressedbetween the outer surface and the lip.

In the alternative or additionally thereto, in the foregoing embodiment,the o-ring and the contour are proximate to a distal end segment of thefirst portion.

In the alternative or additionally thereto, in the foregoing embodiment,the o-ring is located axially outward from the contour.

In the alternative or additionally thereto, in the foregoing embodiment,the tube is made of a material that is harder than a material of thelip.

In the alternative or additionally thereto, in the foregoing embodiment,the wall and the lip are part of a liner.

In the alternative or additionally thereto, in the foregoing embodiment,the vessel includes a layer enveloping the wall with the flange disposedbetween the wall and the layer and the first portion projects throughthe layer.

In the alternative or additionally thereto, in the foregoing embodiment,the layer is made of a composite and the liner is blow molded plastic.

In the alternative or additionally thereto, in the foregoing embodiment,the composite is a resin impregnated fiber.

A pressure vessel assembly according to another, non-limiting,embodiment includes a first vessel including a first wall defining afirst chamber and a circumferentially continuous first lip projectinginto the first chamber from the first wall, the first lip defining afirst through-bore in fluid communication with the first chamber; asecond vessel including a second wall defining a second chamber and acircumferentially continuous second lip projecting into the secondchamber from the second wall, the second lip defining a secondthrough-bore in fluid communication with the second chamber; and anozzle assembly including a tube projecting at least in-part into thefirst and second through-bores, a first o-ring disposed between and insealing contact with the tube and the first lip, and a second o-ringdisposed between and in sealing contact with the tube and the secondlip.

Additionally to the foregoing embodiment, the nozzle assembly includes aflange projecting radially outward from the tube and disposed betweenthe first and second walls.

In the alternative or additionally thereto, in the foregoing embodiment,the nozzle assembly includes a first contour projecting radially outwardfrom the tube and in contact with the first lip, and a second contourprojecting radially outward from the tube and in contact with the secondlip.

In the alternative or additionally thereto, in the foregoing embodiment,the first and second contours and the first and second o-rings areproximate to distal end segments of the respective first and secondlips.

In the alternative or additionally thereto, in the foregoing embodiment,the first vessel includes a first layer enveloping the first wall, thesecond vessel includes a second layer enveloping the second wall andin-part in contact with the first layer, and wherein the tube projectsthrough the first and second layers.

In the alternative or additionally thereto, in the foregoing embodiment,the first and second contours are circumferentially continuous barbs.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. However, it should be understood that the followingdescription and drawings are intended to be exemplary in nature andnon-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiments. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a perspective view of a pressure vessel assembly configured tostore a pressurized fluid according to an exemplary embodiment of theinvention;

FIG. 2 is an exploded perspective view of liners of the pressure vesselassembly;

FIG. 3 is a cross section of the liners;

FIG. 4 is a perspective cross section of the liners with a mid-layerapplied;

FIG. 5 is a perspective cross section of the pressure vessel assembly;and

FIG. 6 is a perspective cross section of the pressure vessel assemblywith integrated nozzle assemblies;

FIG. 7 is an enlarged cross section of a supply nozzle assembly of thepressure vessel assembly; and

FIG. 8 is an enlarged cross section of a transfer nozzle assembly of thepressure vessel assembly.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, an example of a pressure vessel or tankassembly 20 configured to store a high pressure fluid is illustrated.Exemplary fluids that may be stored within the pressure vessel 20include, but are not limited to, compressed natural gas (CNG), hydrogen,propane, methane, air, and hydraulic fluid, for example. The pressurevessel assembly 20 may generally include two flanking vessels 22, 24 andat least one interior vessel 26 (e.g., five identical interior vesselsillustrated) joined to and disposed between the flanking vessels 22, 24.Each vessel 22, 24, 26 may generally be elongated with the overallconfiguration of the pressure vessel assembly 20 generally being arectangular shape, but as will be appreciated from the description,herein, other shapes are contemplated.

Referring to FIG. 2, each vessel 22, 24, 26 may include respectiveliners 28, 30, 32. Each liner 28, 30, 32 may define the boundaries ofrespective chambers 34, 36, 38 for the fluid storage. The flanking endliners 28, 30 may include respective lobes 46, 48 with lobe 46closed-off by opposite end caps 50, 52 and lobe 46 closed-off byopposite end caps 54, 56. Each lobe 46, 48 may be circumferentiallycontinuous and substantially cylindrical. The interior liner 32 mayinclude a lobe 58 with the lobe 58 closed-off by opposite end caps 59,61. Lobe 58 may be circumferentially continuous. The liners 28, 30, 32may be made of any material and thicknesses capable of providing thenecessary structural support, weight, operating characteristics, costlimitations and other parameters necessary for a particular application.Examples of liner material may include steel or other metalliccompositions and plastic. The liners 28, 30, 32 may further be blowmolded plastic, or injection molded plastic with the end caps being anintegral and unitary part of the lobes.

Referring to FIG. 3, the lobes 46, 48 of the respective flanking liners28, 30 may be substantially identical and are arranged such that thelobe 46 of the first flanking liner 28 is rotated about one-hundred andeighty (180) degrees relative to the lobe 48 of the opposite flankingliner 30 (i.e., are arranged as a mirror image of one-another). Eachflanking lobe 46, 48 may include a generally cylindrical outer portionor wall 60 and an interior portion or wall 62. The interior wall 62 maybe substantially planar and may laterally span between a first end 64and a second end 66 of the cylindrical outer wall 60. In one embodiment,the interior wall 62 is integrally formed with the ends 64, 66 of thecylindrical outer wall 60. At least a portion of the curvature of thecylindrical outer wall 60 is defined by a radius R. In one embodiment,the portion of the outer wall 60, opposite the interior wall 62,includes a circular shape or curve generally of a two-hundred and forty(240) degree angle as defined by the radius R. Consequently, the overallheight of the flanking lobes 46, 48 is equal to double the length of theradius R of the cylindrical outer wall 60. The interior wall 62 (i.e.,disposed vertically per the landscape illustrative perspective of FIG.3) is generally parallel to and spaced apart from a vertical plane Pthat includes the origin of the radius R that defines the curvature ofthe outer wall 60. In one embodiment, the distance between the interiorwall 62 and the parallel vertical plane P is about half the length ofthe radius R. As a result, the flanking lobes 46, 48 generally have awidth equal to about one and a half the length of the radius ofcurvature R of the outer wall 60.

The illustrated interior lobe 58 includes first and second interiorsidewalls 68, 70 that may be diametrically opposite one another,substantially vertically arranged, and separated from one another by adistance. In one embodiment, the width of the interior lobe 58 isgenerally equal to the radius of curvature R of the end lobes 46, 48.The thicknesses of the first interior sidewall 68 and the secondinterior sidewall 70 may be identical and may be equal to the thicknessof the interior wall 62 of the flanking lobes 46, 48. A first outsidewall 72 extends between a first end 74 of the first interior sidewall 68and a first end 76 of the second interior sidewall 70. Similarly, asecond outside wall 78 extends between a second end 80 of the firstinterior sidewall 68 and a second end 82 of the second interior sidewall70.

The curvature of the first outside wall 72 and the second outside wall78 may be defined by a circular shape or curve generally of a sixty (60)degree angle by a radius R. In one embodiment, the radius of curvature Rof the interior lobe 58 is substantially identical to the radius ofcurvature R of the flanking lobes 46, 48. Consequently, the distancebetween the first curved wall 72 and the second curved wall 78 is doublethe length of the radius of curvature R, and is therefore, substantiallyequal to the height of the flanking lobes 46, 48.

Referring to FIG. 4, the vessels 22, 24, 26 each include a mid-layer 84,86, 88 that substantially covers the respective liners 28, 30, 32. Themid-layer 84 may be a continuous fiber wrapping or prepregs (i.e., fiberwith resin) wrapped about the lobes and end caps of the liners forstructural strength and for distributing internal stress. Alternatively,the mid-layers 84, 86, 88 may include a braiding that wraps about therespective liners 28, 30, 32. The primary reinforcement (i.e., thefibers or braiding), may be made of a carbon fiber, a glass fiber or anaramid fiber. A matrix material or resin for binding the continuousfibers may include epoxy, vinyl ester and other resin systems that maybe nano-enhanced. It is further contemplated and understood that themid-layers 84, 86, 88 may be made of resin impregnated fibers that maybe chopped. As one example, the chopped fibers may be about one (1) inch(2.54 cm) in length.

When the pressure vessel assembly 20 is at least partially assembled,the interior wall 62 of the flanking lobe 46 is opposed and in proximityto the interior sidewall 68 of the interior lobe 58. The portion of themid-layer 84 covering the interior wall 62 may be directly adjacent andadhered to the portion of the mid-layer 88 that covers the sidewall 68.Adherence may be achieved when the vessel assembly 20 is cured.Similarly, the interior wall 62 of the flanking lobe 48 is opposed andin proximity to the interior sidewall 70 of the interior lobe 58. Theportion of the mid-layer 86 covering the interior wall 62 may bedirectly adjacent and adhered to the portion of the mid-layer 88 thatcovers the sidewall 70.

Referring to FIG. 5, the composite vessel assembly 20 may include anouter layer 90 that generally covers and envelops the inner-layers 84,86, 88. The outer layer 90 may be applied after the inner-layers 84, 86,88 are joined. The outer layer 90 may be a composite, and may be amixture of a non-continuous (e.g., chopped) fiber and resin that may bespray applied (i.e., spray chop fiber/resin) or may be a sheet moldingcompound (SMC). The primary reinforcement (i.e., the chopped fibers),may be made of a carbon fiber, a glass fiber or an aramid fiber of aboutone (1) inch in length (2.5 cm). The resin for binding the choppedfibers may include epoxy, vinyl ester and other resin systems that maybe nano-enhanced. It is contemplated and understood that theinner-layers 84, 86, 88 may also be similar in composition andapplication process as the outer layer 90.

The pressure vessel assembly 20 may further include a plurality ofjunctions 92 with each junction located where respective ends of theouter walls 60, 72, 78, ends of the sidewalls 68, 70, and ends ofinterior walls 62 generally meet. Each junction 92 may generally beY-shaped (i.e., a three pointed star) and may be made of the samematerial as the outer layer 90.

In one embodiment where continuous fiber is utilized for theinner-layers 84, 86, 88 and the chopped fiber is used for the outerlayer 90, the vessel assembly 20 may be much lighter in weight than ifthe entire assembly were made with a chopped fiber. However, theinternal structural sidewalls 68, 70 and internal walls 62 may havedifferent thicknesses (e.g., about half as thick) than the outer walls60, 72, 78 with the hybrid of continuous fiber and chopped fiber. Forthis embodiment of hybrid composite wall construction, the internalstructural sidewalls 68, 70 and internal walls 62 may have a higher orlower effective stiffness than the hybrid outer walls 60, 72, 78, andtherefore the junctions 92 will require an optimized angle that isdifferent from about one-hundred and twenty (120) degrees that wouldtypically be derived from homogeneous materials. The junction 92 angleand the internal wall thickness can be optimized based on specificmaterial properties and hybrid wall construction.

Referring to FIGS. 6 and 7, the pressure vessel assembly 20 may includeat least one supply nozzle assembly 94 (i.e., two illustrated) and atleast one transfer nozzle assembly 96 (i.e., two illustrated). Thesupply nozzle assembly 94 is configured to flow the pressurized fluidinto or out of any one or more of the chambers 40, 42, 44. The transfernozzle assembly 96 is configured to flow the pressurized fluid betweenchambers 40, 42, 44. As applied herein, the term “supply” refers to theflow of a fluid (i.e. liquid or gas) into and/or out of the pressurevessel assembly 20. For ease of explanation, the nozzle assemblies 94,96 will be described with reference to the first and mid vessels 22, 26;however, it is understood that the nozzle assemblies may be mounted toany one of a number of vessels and in any variety of configurations. Itis further understood and contemplated that many novel attributesbetween the nozzle assemblies 94, 96 of the present disclosure may bethe similar although the applications between the nozzle assemblies maybe different.

The liner 28 of the first vessel 22 may include a wall 98 that generallydefines the boundaries of the chamber 40, and a lip 100 that projectsinto the chamber 40 from the wall 98. The lip 100 may becircumferentially continuous and defines a through-bore 102 in fluidcommunication with the chamber 40. In one embodiment, the liner 28 maybe one unitary piece and made of a blow molded plastic.

The supply nozzle assembly 94 may include a tube 104 and a flange 106that projects radially outward from the tube 104 and may becircumferentially continuous (i.e. annular). The flange 106 is generallydisposed and in contact between the wall 98 of the liner 28 and themid-layer 84. The tube 104 may provide direct fluid communicationbetween the chamber 40 and the environment outside of the pressurevessel assembly 20. The tube 104 may include a first portion 108 thatprojects inward from the flange 106, and substantially into thethrough-bore 102. When the first portion 108 is fully inserted into thethrough-bore 102, a distal end segment or rim 109 may be substantiallyaxially aligned with a distal end segment 111 of the lip 100. Anopposite portion 110 of the tube 104 projects from the flange 106 in asubstantially opposite direction from the first portion 108, and throughthe mid and outer layers 84, 90.

During assembly, the first portion 108 of the tube 104 is press fittedagainst the lip 100 and into the through-bore 102. The tube portion 108carries a surface 112 that generally faces radially outward. The surface112 may include or define at least one contour 114 (i.e., oneillustrated). The contour 114 is generally located at the distal endsegment 109 of the first portion 108 and may be configured to provide aseal between the distal end segment 109 of the tube 104 and the distalend segment 111 of the liner lip 100. Moreover, the contour 114 mayprovide a degree of friction that, at least in-part, preventsdislodgement of the tube 104 from the first vessel 22. A non-limitingexample of a contour 114 may be a circumferentially continuous barb. Thebarb 114 may be further configured to assist in the insertion of thetube 104 into the lip 100 (i.e., via a ramp carried by the barb), whileresisting withdrawal of the tube from the lip. Furthermore, and afterfinal assembly, the dislodgement or withdrawal of the tube 104 from theliner 28 is further prohibited by the mid and outer layers 84, 90 placeover the flange 106 and up to (i.e. tightly surrounding) the outerportion 110.

The supply nozzle assembly 94 may further include a resilientlycompressible o-ring 115 that facilitates a seal between the tube 104 andthe lip 100 of the liner 28 whether or not the chamber 40 is under ahigh pressure condition. In contrast, the barb 114 may provide a furtherseal between the tube 104 and the lip 100 during relatively highpressure conditions but not necessarily low or no pressure conditionsdepending, at least in-part, upon the flexibility of the lip 100. Theo-ring 115 may be seated in a circumferentially continuous groove 117having boundaries defined by the surface 112. The groove 117 may be inthe distal end segment 109 of the tube portion 108, and may be definedin-part by the barb 114 (i.e., the barb is directly adjacent to thegroove). When the pressure vessel assembly 20 is fully assembled, theo-ring 115 is resiliently compressed between the distal end segment 109of the tube portion 108 and the distal end segment 111 of the lip 100.

The supply nozzle assembly 94 may be made of a metallic alloy that maybe one unitary piece requiring no or minimal machining. The liner 28 maybe made of a blow molded plastic that may be compliant with respect tothe nozzle assembly. That is, the nozzle assembly 94 and the liner 28may be made out of any variety of materials with the nozzle assembly 94material being harder than the liner 28 material. This difference inhardness assists sealing engagement of the barbs 114 against the lip100. Moreover, pressurized use of the pressure vessel assembly 20produces a biasing force (see arrows 116) against the lip 100 and wall98 thus pressing the lip and wall against the respective tube portion108 and flange 106, further promoting the desired sealing relationshipof the nozzle assembly 94 to the liner 28.

Referring to FIGS. 6 and 8, the liner 28 of the first vessel 22 mayinclude a second lip 118 that projects into the chamber 40 from the wall98. The lip 118 may be circumferentially continuous and defines athrough-bore 120 in fluid communication with the chamber 40. In the sameproximity, the liner 32 of the vessel 26 may include a wall 122 thatdefines the chamber 44, and a third lip 124 that projects into thechamber 44 from the wall 122. The lip 124 may be circumferentiallycontinuous and defines a through-bore 126 in fluid communication withthe chamber 44.

The transfer nozzle assembly 96 may include a tube 128 and a flange 130that projects radially outward from the tube 128 and may becircumferentially continuous (i.e. annular). The flange 130 is generallydisposed and in contact between the liner walls 98, 122 of therespective liners 28, 32. The tube 128 may provide direct fluidcommunication between the chambers 40, 44. The tube 128 may include afirst portion 132 that projects from the flange 130, through thethrough-bore 120 and generally into the chamber 40. An opposite portion134 of the tube 128 projects from the flange 130 in a substantiallyopposite direction from the first portion 132, through the through-bore126 and generally into the chamber 44.

During assembly, the first and second portions 132, 134 of the tube 128are press fitted against the respective lips 118, 124 and into therespective through-bores 120, 126. Similar to the supply nozzle assembly94, the tube portions 132, 134 may each carry an outer surface thatdefines a respective barb 135. The barbs 135 may be configured to assistin the insertion of the tube 128 into the lips 118, 124, while resistingwithdrawal of the tube from the lips. Also similar to the supply nozzleassembly 94, the transfer nozzle assembly 96 may further include twoo-rings 137 respectively compressed between first and second tubeportions 132, 134 and respective lips 118, 124.

The transfer nozzle assembly 96 may be made of a metallic alloy that maybe one unitary piece requiring no or minimal machining. The liners 28,32 may be made of a blow molded plastic that may be compliant withrespect to the nozzle assembly. That is, the nozzle assembly 96 and theliners 28, 32 may be made out of any variety of materials with thenozzle assembly 96 material being harder than the material of the liners28, 32. This difference in hardness assists sealing engagement of thebarbs (not shown) against the lips 118, 124. Moreover, pressurized useof the pressure vessel assembly 20 produces a biasing force against thelips 118, 124 and walls 98, 122 thus pressing the lips and walls againstthe respective tube portions 132, 134 and flange 130 further promotingthe desired sealing relationship of the nozzle assembly 96 to the liners28, 32.

The mid-layers 84, 88 may generally include adjacent boss segments 138that generally surround the outer perimeter of the flange 130. The bosssegments 138 may generally be an annular volume where both layers 84, 88are increased in thickness to provide greater structural support at thevicinity of the transfer nozzle assembly 96. The walls 98, 122 of therespective liners 28, 32 may be recessed or contoured for providing thenecessary space required by the boss segments 138.

The composite pressure vessel assembly 20 may provide a lightweightstorage tank(s) with a high energy storage density. The approach enablesthe easy addition of reinforcing composite material where needed (e.g.junctions 92). The use of the hybrid continuous and short fiber mayfurther minimize the vessel assembly weight. Because the vessel assembly20 is in a non-cylindrical shape, the assembly will provide the highestconformability to a given space. Moreover, the composite constructionwill also provide corrosion resistance compared to metallic tanks.

The present disclosure also provides a cost effective solution injoining a nozzle assembly that may be metallic with a liner that may bea polymer. That is, the liners may be produced using an inexpensive flowmolding process and machining costs of the metallic nozzle assembly isless expensive due to a simpler geometry when compared to traditionalnozzle assemblies. Moreover, the static lip seal arrangement provides anelegant and simple solution, not only for a vessel port, but also forconnecting multiple chambers internally and adaptable over a wide rangeof pressure.

While the present disclosure is described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the spirit and scope of the present disclosure. Inaddition, various modifications may be applied to adapt the teachings ofthe present disclosure to particular situations, applications, and/ormaterials, without departing from the essential scope thereof. Thepresent disclosure is thus not limited to the particular examplesdisclosed herein, but includes all embodiments falling within the scopeof the appended claims.

What is claimed is:
 1. A pressure vessel assembly comprising: a vesselincluding a wall defining a chamber and a circumferentially continuouslip projecting into the chamber from the wall, the lip defining athrough-bore in fluid communication with the chamber; and a nozzleassembly including a tube projecting at least in-part into thethrough-bore, and an o-ring disposed between and in sealing contact withthe tube and the lip, wherein the nozzle assembly includes a flangeprojecting radially outward from the tube and in contact with the wall,wherein the tube includes a first portion projecting axially inward fromthe flange and into the through-bore and an opposite second portionprojecting axially outward from the flange, wherein the first portionincludes an outer surface having a contour constructed and arranged toengage the lip, wherein the contour is circumferentially continuous, andwherein the vessel includes a layer enveloping the wall with the flangedisposed between the wall and the layer and the first portion projectsthrough the layer.
 2. The pressure vessel assembly set forth in claim 1,wherein the contour is a barb constructed and arranged to produce asealing friction between the lip and the outer surface when the pressurevessel assembly is under a positive pressure.
 3. The pressure vesselassembly set forth in claim 2, wherein an internal pressure in thechamber biases the lip radially inward against the barb, and wherein theo-ring is resiliently compressed between the outer surface and the lip.4. The pressure vessel assembly set forth in claim 1, wherein the o-ringand the contour are proximate to a distal end segment of the firstportion.
 5. The pressure vessel assembly set forth in claim 4, whereinthe o-ring is located axially outward from the contour.
 6. The pressurevessel assembly set forth in claim 1, wherein the tube is made of amaterial that is harder than a material of the lip.
 7. The pressurevessel assembly set forth in claim 1, wherein the wall and the lip arepart of a liner.
 8. The pressure vessel assembly set forth in claim 1,wherein the wall and the lip are part of a liner, and the layer is madeof a composite and the liner is blow molded plastic.
 9. The pressurevessel assembly set forth in claim 8, wherein the composite is a resinimpregnated fiber.
 10. A pressure vessel assembly comprising: a firstvessel including a first wall defining a first chamber and acircumferentially continuous first lip projecting into the first chamberfrom the first wall, the first lip defining a first through-bore influid communication with the first chamber; a second vessel including asecond wall defining a second chamber and a circumferentially continuoussecond lip projecting into the second chamber from the second wall, thesecond lip defining a second through-bore in fluid communication withthe second chamber; and a nozzle assembly including a tube projecting atleast in-part into the first and second through-bores, a first o-ringdisposed between and in sealing contact with the tube and the first lip,and a second o-ring disposed between and in sealing contact with thetube and the second lip, wherein the nozzle assembly includes a flangeprojecting radially outward from the tube and disposed between the firstand second walls, and wherein the first vessel includes a first layerenveloping the first wall, the second vessel includes a second layerenveloping the second wall and in-part in contact with the first layer,and wherein the tube projects through the first and second layers. 11.The pressure vessel assembly set forth in claim 10, wherein the nozzleassembly includes a first contour projecting radially outward from thetube and in contact with the first lip, and a second contour projectingradially outward from the tube and in contact with the second lip. 12.The pressure vessel assembly set forth in claim 11, wherein the firstand second contours and the first and second o-rings are proximate todistal end segments of the respective first and second lips.
 13. Thepressure vessel assembly set forth in claim 11, wherein the first andsecond contours are circumferentially continuous barbs.